| In the middle of1960s, the Swedish scientist Branemark firstly put up theBone Bonding Theory which became the base of modern implant dentistry. Thistheory has unsurpassed advantages over the traditional denture, such as morebeautiful, more comfortable, not damaging the temporary teeth, better chewfunction. It has been reported that the success rate of this Implant-supportedProsthesis meets more than90percent. In clinical practice, the aged patientswith dentition defect take great proportion, and some of them has OP. When themetabolism of patients’ whole body and jaws are affected by the diseases,implant fracture, loose and lost follows. It makes great risk to takingimplantation. With the constant development of oral technology, theimprovement of implant denture is not supposed to neglect. Implant dentureperforms well in clinical practice to repair dentition defect, however, only fewpatients with dentition defect are accessible to the implant operation. One of themain reason is the long treatment period. In order to shorten the treatment circle,some scholars propose the concept of early-loaded which could shorten thetreatment period and preserve the amount of bone formation in the implanted area as well as alleviate pain for patients due to the many times of surgeries. EIis initially applied to industrial area. It is orthopaedics that firstly improves itand makes it work for rigid internal fixation in the situation of Osteoporosis.However, it has never been reported that EI is used for Oral and Maxillofacial.So this experiment is going to compare EI, a new type implant, to traditionalCI、ATI、NTI.Part one：Establishing the3-D Finite Element Model which includesfour different shapes of dental implants under different bone conditionsPurpose: Establishing the3-D Finite Element Model which includescylindrical implant(CI), apical tapered implant(ATI), neck tapered implant(NTI),expandable implant(EI) and mandible bone to simulate the bone formationunder the different condition. To supply for modle for the researches focusing onthe biochemical charactetisctics of CI, ATI, NTI and EI.Methods: With the assistance of Pro/E Establishing the3-D Finite ElementModel which includes CI,ATI,NTI,EI and mandible bone to simulate the boneformation under the condition of normal bone, OP and early-loaded viaadjusting jaw parameters.Results: We Establishs the3-D Finite Element Model which includes CI,ATI, NTI, EI and mandible bone with different bone characteristics, and themodel could simulate the bone formation under the condition of normal bone,OP and early-loaded via adjusting jaw parameters and the type of friction.Conclusions: This research largely improves the efficiency and accuracyof building modles by using the modle established by the self-adjusting fuctionof Pro/E software, the seamless interface between Ansys Workbench andPro/E, and the bidirectional transmission function. It offers reliable modle forthe reseaches aiming at the study of biochemical charactetrisctics of CI, ATI, NTI and EI.Part two：Three dimensional finite element analysis of cylindricalimplant, apical tapered implant, neck tapered implant and expandableimplants in normal bone conditionsPurpose: With the assistance of Pro/E and Ansys workbench, this subject,centering on biomechanics, is to analysis the biomechanics characteristics ofcommon implants and EI in the normal bone.Method: Applying100N AX force and30N BL force to the implants andselecting cortical bone and cancellous bone, the Max EQV and the Maxdisplacement in implant-abutment as the evaluation standard.Results: In the case of normal bone, in cortical bone，comparing to CI,when the BL force increases, the highest EQV of NTI decreases by6.75%accordingly, and in cancellous bones，the highest EQV of NTI and EI reduce by4.21%and7.91%respectively, however, when axial force and BL increase, theMax displacement of NTI reduce by2.06%and12.0%.Conclusions:1. Under the condition of normal bone, neck tapered implant showedbetter stress distribution.2. Under the condition of normal bone, neck tapered implant showed thebest stabilityPart three： Three dimensional finite element analysis of cylindricalthreaded implant, apical tapered implant, neck tapered implant andexpandable implants in osteoporotic conditionsPurpose: With the assistance of Pro/E and Ansys workbench, this subject,centering on biomechanics, is to analysis the biomechanics characteristics ofcommon implants and EI in the osteoporosis bone. Method: Applying100N AX force and30N BL force to the implants andselecting cortical bone and cancellous bone, the Max EQV and the Maxdisplacement in implant-abutment as the evaluation standard.Results: In the case of osteoporosis bone, comparing to CI, in cortical bone,the highest EQV when AX and BL increase, influenced by ATI, NTI, EI godown by10.1%,6.57%,10.72%,7.87%and11.3%,9.62%. In cancellous bone,when the BL goes up, the highest EQV of NTI reduces by3.56%and when bothof axial and BL increase, the highest EQV of NTI reduces by21.8%and17.4%.Conclusions:1. Under the condition of osteoporosis bone, neck tapered implant andexpandable implant showed better stress distribution.2. Under the condition of osteoporosis bone, neck tapered implant showedthe best stabilityPart four: Three dimensional finite element analysis of cylindrical threadedimplant, apical tapered implant, neck tapered implant and expandableimplants in early-loaded conditions.Purpose: With the assistance of Pro/E and Ansys workbench, this subject,centering on biomechanics, is to analysis the biomechanics characteristics ofcommon implants and EI in the early-loaded condition.Method: Applying100N AX force and30N BL force to the implants andselecting cortical bone and cancellous bone, the Max EQV and the Maxdisplacement in implant-abutment as the evaluation standard.Results: In the early-loaded condition, comparing to CI, in cortical bone,the highest EQV of EI and NTI reduces by15.34%,8.53%and9.38%,12.07%when axial force increase. The Max displacement in implant-abutment of NTIreduces22.52%and15.41%respectively. Conclusions:1. In the early-loaded condition, expandable implant and neck taperedimplant showed better stress distribution.2. In the early-loaded condition, neck tapered implant showed the beststability... |
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